MFC r296419 (by kib):

In the link_elf_obj.c, handle sections of type SHT_AMD64_UNWIND same
as SHT_PROGBITS.  This is needed after the clang 3.8 import, which
generates that type for .eh_frame section, which had SHT_PROGBITS type
before.

Reported by:	Nikolai Lifanov <lifanov@mail.lifanov.com>
PR:		207729
Tested by:	dim (previous version)
Sponsored by:	The FreeBSD Foundation

MFC r296428:

Since kernel modules can now contain sections of type SHT_AMD64_UNWIND,
the boot loader should not skip over these anymore while loading images.
Otherwise the kernel can still panic when it doesn't find the .eh_frame
section belonging to the .rela.eh_frame section.

Unfortunately this will require installing boot loaders from sys/boot
before attempting to boot with a new kernel.

Reviewed by:	kib

Approved by:	re (marius)

2 files changed, 31 insertions, 1 deletions

diff --git a/sys/boot/common/load_elf_obj.c b/sys/boot/common/load_elf_obj.c
index 626f2d9..b983ecb 100644
--- a/sys/boot/common/load_elf_obj.c
+++ b/sys/boot/common/load_elf_obj.c
@@ -221,6 +221,9 @@ __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
 		switch (shdr[i].sh_type) {
 		case SHT_PROGBITS:
 		case SHT_NOBITS:
+#if defined(__i386__) || defined(__amd64__)
+		case SHT_AMD64_UNWIND:
+#endif
 			lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
 			shdr[i].sh_addr = (Elf_Addr)lastaddr;
 			lastaddr += shdr[i].sh_size;
diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c
index 453d8ce..dc13283 100644
--- a/sys/kern/link_elf_obj.c
+++ b/sys/kern/link_elf_obj.c
@@ -257,6 +257,9 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
 		switch (shdr[i].sh_type) {
 		case SHT_PROGBITS:
 		case SHT_NOBITS:
+#ifdef __amd64__
+		case SHT_AMD64_UNWIND:
+#endif
 			ef->nprogtab++;
 			break;
 		case SHT_SYMTAB:
@@ -327,9 +330,16 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
 		switch (shdr[i].sh_type) {
 		case SHT_PROGBITS:
 		case SHT_NOBITS:
+#ifdef __amd64__
+		case SHT_AMD64_UNWIND:
+#endif
 			ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 			if (shdr[i].sh_type == SHT_PROGBITS)
 				ef->progtab[pb].name = "<<PROGBITS>>";
+#ifdef __amd64__
+			else if (shdr[i].sh_type == SHT_AMD64_UNWIND)
+				ef->progtab[pb].name = "<<UNWIND>>";
+#endif
 			else
 				ef->progtab[pb].name = "<<NOBITS>>";
 			ef->progtab[pb].size = shdr[i].sh_size;
@@ -553,6 +563,9 @@ link_elf_load_file(linker_class_t cls, const char *filename,
 		switch (shdr[i].sh_type) {
 		case SHT_PROGBITS:
 		case SHT_NOBITS:
+#ifdef __amd64__
+		case SHT_AMD64_UNWIND:
+#endif
 			ef->nprogtab++;
 			break;
 		case SHT_SYMTAB:
@@ -659,6 +672,9 @@ link_elf_load_file(linker_class_t cls, const char *filename,
 		switch (shdr[i].sh_type) {
 		case SHT_PROGBITS:
 		case SHT_NOBITS:
+#ifdef __amd64__
+		case SHT_AMD64_UNWIND:
+#endif
 			alignmask = shdr[i].sh_addralign - 1;
 			mapsize += alignmask;
 			mapsize &= ~alignmask;
@@ -726,6 +742,9 @@ link_elf_load_file(linker_class_t cls, const char *filename,
 		switch (shdr[i].sh_type) {
 		case SHT_PROGBITS:
 		case SHT_NOBITS:
+#ifdef __amd64__
+		case SHT_AMD64_UNWIND:
+#endif
 			alignmask = shdr[i].sh_addralign - 1;
 			mapbase += alignmask;
 			mapbase &= ~alignmask;
@@ -734,6 +753,10 @@ link_elf_load_file(linker_class_t cls, const char *filename,
 				    ef->shstrtab + shdr[i].sh_name;
 			else if (shdr[i].sh_type == SHT_PROGBITS)
 				ef->progtab[pb].name = "<<PROGBITS>>";
+#ifdef __amd64__
+			else if (shdr[i].sh_type == SHT_AMD64_UNWIND)
+				ef->progtab[pb].name = "<<UNWIND>>";
+#endif
 			else
 				ef->progtab[pb].name = "<<NOBITS>>";
 			if (ef->progtab[pb].name != NULL && 
@@ -755,7 +778,11 @@ link_elf_load_file(linker_class_t cls, const char *filename,
 			}
 			ef->progtab[pb].size = shdr[i].sh_size;
 			ef->progtab[pb].sec = i;
-			if (shdr[i].sh_type == SHT_PROGBITS) {
+			if (shdr[i].sh_type == SHT_PROGBITS
+#ifdef __amd64__
+			    || shdr[i].sh_type == SHT_AMD64_UNWIND
+#endif
+			    ) {
 				error = vn_rdwr(UIO_READ, nd.ni_vp,
 				    ef->progtab[pb].addr,
 				    shdr[i].sh_size, shdr[i].sh_offset,